Research is conducted with human volunteers involving study of an experimental analogue of non-opiate drug abuse. Within a residential research setting volunteer drug abusers are permitted to self-administer various sedative stimulant compounds (barbiturates, benzodiazepines, amphetamine, cocaine) under experimentally controlled conditions. The approach and techniques of the experimental analysis of behavior are utilized to identify and study factors which act as controlling variables of such human drug self-administration. The aim is to identify behavioral and environmental factors which can be manipulated to control, modify and reduce drug intake. The results will contribute to improved understanding of and treatment procedures for non-opiate drug abuse. Initial studies have examined the effects of manipulating response cost, minimum inter-ingestion interval and drug dose on human sedative self-administration.